FIG. 1 illustrates in part a known coin processing machine 10 used for counting US currency, that is, for counting US coins (in decreasing coin diameter): half-dollars, dollars, quarter-dollars, nickels, pennies, and dimes. The coin processing machine 10 is described in my U.S. Pat. No. 8,172,654 “Coin Processing Machine with Pivoting Alignment Finger” that issued May 8, 2012, the disclosure of which is incorporated by reference as if fully set forth herein. The coin processing machine 10 has proven in practice to be a reliable and durable device that accurately sorts, counts, or verifies coins (even wet or oily coins) at high speed.
Coin processing machine 10 has a rotatable turntable 12 mounted in stationary plate 14. Turntable 12 has an upper coin support surface 16 flush with upper coin support surface 18 of plate 14.
Stationary raking finger 20 and stationary guide finger 22 are mounted on plate 14. Raking finger 20 and guide finger 22 define a first opening 24 that receives a singulated stream of coins from turntable 12. A raised peripheral wall (not shown) mounted to plate 14 partially surrounds the turntable 12 and has an opening aligned with opening 24 to enable coins leaving turntable 14 to move between fingers 20 and 22.
A belt drive for driving the singulated stream of coins along the plate 14 is disclosed in my U.S. Pat. No. 7,243,774 “High Speed Coin Processing Machine” that issued Jul. 17, 2007, the disclosure of which is incorporated by reference as if fully set forth herein. The belt drive (not shown) has a belt run located above plate 14. The belt run engages coins entering opening 24 and accelerates the coins towards coin through-slot 26 formed in plate 14. The belt drive spaces the coins apart as the coins move towards slot 26. The belt run urges the coins to move in a downstream direction along a first, planar guide surface 28. The belt preferably also urges the coins towards the guide surface 28 (that is, the belt run does not extend parallel with guide surface 28 but extends towards surface 28 in the downstream direction as the belt run extends towards slot 26).
Sensors 30b carried in plate 14 are located between opening 24 and slot 26. Each sensor 30b is associated with a different diameter coin (half-dollar, dollar, quarter-dollar, nickel, penny, dime) and is spaced a predetermined distance from the guide surface 28. The sensors 30b are arranged to first detect the largest diameter coin (in the illustrated embodiment a US half-dollar coin) and then detect each succeeding smaller-diameter coin as a coin in contact with guide surface 28 passes sensors 30a. The sensors 30a are connected to a controller (not shown) that records the denomination of each coin passing the sensors 30a and maintains a running count of the value of the coins discharged from the turntable 12.
A pair of sensors 30a associated with the half dollar and dollar coins are also carried in plate 14 and cooperate with respective half dollar and dollar coin sensors 30a as described in my co-pending U.S. patent application Ser. No. 13/223,858 “Coin Processing Machine with Dual Rows of Coin Sensors” filed 1 Sep. 2011, which application is incorporated by reference as if fully set forth herein.
A pivotable alignment finger 34 is mounted on plate 14 downstream from rake finger 20. Alignment finger 34 has a free end 36 that is spaced away from the first guide surface 28. The alignment finger 34 and the guide surface 28 define a second opening 37 that is downstream from the first opening 24 along the guide surface 28.
Alignment finger 34 pivots about mounting fastener 38. The range of motion of finger 34 is established by dowel pin 40 in circumferentially-elongate finger slot 42 between a normal operating position towards rake finger 20 and a retracted position away from rake finger 20. A spring 44 formed from thin spring steel plate engages finger 34 and urges the free end 36 of finger 34 towards the normal operating position.
Free end 36 of finger 34 extends sufficiently towards the first opening 24 to contact and engage larger-diameter coins passing through the opening as the coins move along guide surface 28. In other words, the width of the second opening 37 is less than the largest diameter of coin to be processed. Free end 36 includes a second guide surface 45 that faces the first opening 24. Guide surface 45 extends in a downstream direction towards the first guide surface 28.
When a larger-diameter coin passes through first opening 24, the coin contacts end 36 of finger 34 as it bears against guide surface 28. The lower belt run (represented schematically as arrow 47 extending in the downstream direction along the guide surface 28) forces the coin past alignment finger 34, deflecting spring 44 and moving the alignment finger 34 towards its retracted position. Movement of the alignment finger 34 enables the coin to continue moving through second opening 37 and pass by the finger end 36. Spring 44 urges the alignment finger quickly back to its normal position after the coin passes the alignment finger 34.
When a smaller-diameter coin passes through first opening 24 the alignment finger 34 is in its normal operating position as shown in FIG. 1. A smaller-diameter coin that is located closer to the raking finger 20 than the guide finger 22 may engage second guide surface 45 of the alignment finger 34 after the coin moves through the opening 24. Second guide surface 45 is configured to redirect the coin towards first guide surface 28 as the belt forces the coin downstream towards the second opening 37. The smaller-diameter coin has a diameter less than the opening 37 (that is, the smaller-diameter coin has a diameter less than the distance between finger 34 and guide surface 28 when the finger 34 is in its normal position).
The smaller-diameter coin is not compressed between finger 34 and guide surface 28 when it reaches the end of the guide surface 45 and enters the second opening 37, and so the smaller-diameter coin does not force the finger 34 away from its normal operating position. After the smaller-diameter coin passes finger 34, the belt continues the component of coin travel towards guide surface 28 to assure that the coin engages the guide surface 28 before reaching the sensors 30 for accurate discrimination and counting.
When a smaller-diameter coin is away from the raking finger 22 when passing through first opening 24, the coin may not engage finger 34. The coin, however, is sufficiently close to guide surface 28 that the belt will properly align the coin with respect to surface 28 before the coin reaches sensors 30.
If a larger-diameter coin is followed by a smaller-diameter coin, the spring 44 moves alignment finger 34 back to its normal position quickly so that the smaller-diameter coin may engage the guide surface 45 and be directed towards the guide surface 28 before the smaller-diameter coin reaches the second opening 37. Preferably the guide surface 45 extends towards the first guide surface 28 even when the alignment finger 34 has not yet returned to its normal position.
Alignment finger 34 is preferably mounted on plate 14 with a small amount of vertical play 46 (see FIG. 2) that enables the finger to move towards and away plate 14. The amount of play must be less than the minimum coin thickness, and is intended to enable dirt and other contaminants to pass under finger 34 without buildup. Spring 44 has an upper portion 49 that extends above and overhangs finger 34 with sufficient clearance to enable the desired vertical play. After lifting off plate 14, the upper surface of finger 34 engages the overhanging spring portion 49 to prevent further vertical movement of the finger.
The coin processing machine 10 reliably counts even wet or oily coins. However, if one of the coin sensors 30 (shown for example the half-dollar coin sensor 30a) is covered by a small piece of stray metal, the covered coin sensor 30a will always signal to the controller the presence of a coin even if the coin passing by the sensor 30a is a coin of a smaller diameter coin than the coin diameter associated with the sensor 30a. This problem is generally not a major problem with the sensors downstream from the most upstream sensor (the sensor associated with the largest diameter coin) because a coin will come by and sweep the metal off the sensor. However, the illustrated most upstream sensor 30a is associated with the half-dollar coin, and it may be quite awhile before another half-dollar coin comes along that will sweep any unwanted metal off the sensor 30a. As a result, there can be a substantial period during which coins that are not half-dollar coins may be miscounted as half-dollar coins.
Thus there is a need for an improved sensor arrangement that does not miscount the largest diameter coins because of metal contaminants overlying the sensor associated with those coins.